I've heard there are high levels of trip reroutes and cancellations. Basically you're going to be late and/or rescheduled into RR overnights and lots of MX problems on the order of every-other leg. Apparently planes aren't fixed until they're routed through CAE with deferrals and repeats stacking up until the plane gets there. ORD is not a MX base, and IAD has limited expertise nor parts to fix anything. I looked into this as well because like you I'd be unbelievably senior, but I hear nothing but complaints about the operation. It seems they've all but forgotten about the operation because it won't last anyway at the rate it's going. United is likely to pull the plug when the contract expires.
Commutability is probably a huge factor as well. Delta has reduced frequency from ATL, and the area is extremely expensive to live in.